Efficacy and Safety of Appropriate Shocks and Antitachycardia Pacing in Transvenous and Subcutaneous Implantable Defibrillators: Analysis of All Appropriate Therapy in the PRAETORIAN Trial

Reinoud E Knops, Willeke van der Stuijt, Peter Paul H M Delnoy, Lucas V A Boersma, Juergen Kuschyk, Mikhael F El-Chami, Hendrik Bonnemeier, Elijah R Behr, Tom F Brouwer, Stefan Kaab, Suneet Mittal, Lonneke Smeding, Jan G P Tijssen, Nick R Bijsterveld, Sergio Richter, Marc A Brouwer, Joris R de Groot, Kirsten M Kooiman, Pier D Lambiase, Petr NeuzilKevin Vernooy, Marco Alings, Timothy R Betts, Frank A L E Bracke, Martin C Burke, Jonas S S G de Jong, David J Wright, Ward P J Jansen, Zachary I Whinnett, Peter Nordbeck, Michael Knaut, Berit T Philbert, Jurren M van Opstal, Alexandru B Chicos, Cornelis P Allaart, Alida E Borger van der Burg, Jude F Clancy, Jose M Dizon, Marc A Miller, Dmitry Nemirovsky, Ralf Surber, Gaurav A Upadhyay, Raul Weiss, Anouk de Weger, Arthur A M Wilde, Louise R A Olde Nordkamp, PRAETORIAN Investigators


BACKGROUND: The PRAETORIAN trial (A Prospective, Randomized Comparison of Subcutaneous and Transvenous Implantable Cardioverter Defibrillator Therapy) showed noninferiority of subcutaneous implantable cardioverter defibrillator (S-ICD) compared with transvenous implantable cardioverter defibrillator (TV-ICD) with regard to inappropriate shocks and complications. In contrast to TV-ICD, S-ICD cannot provide antitachycardia pacing for monomorphic ventricular tachycardia. This prespecified secondary analysis evaluates appropriate therapy and whether antitachycardia pacing reduces the number of appropriate shocks.

METHODS: The PRAETORIAN trial was an international, investigator-initiated randomized trial that included patients with an indication for implantable cardioverter defibrillator (ICD) therapy. Patients with previous ventricular tachycardia <170 bpm or refractory recurrent monomorphic ventricular tachycardia were excluded. In 39 centers, 849 patients were randomized to receive an S-ICD (n=426) or TV-ICD (n=423) and were followed for a median of 49.1 months. ICD programming was mandated by protocol. Appropriate ICD therapy was defined as therapy for ventricular arrhythmias. Arrhythmias were classified as discrete episodes and storm episodes (≥3 episodes within 24 hours). Analyses were performed in the modified intention-to-treat population.

RESULTS: In the S-ICD group, 86 of 426 patients received appropriate therapy, versus 78 of 423 patients in the TV-ICD group, during a median follow-up of 52 months (48-month Kaplan-Meier estimates 19.4% and 17.5%; P=0.45). In the S-ICD group, 83 patients received at least 1 shock, versus 57 patients in the TV-ICD group (48-month Kaplan-Meier estimates 19.2% and 11.5%; P=0.02). Patients in the S-ICD group had a total of 254 shocks, compared with 228 shocks in the TV-ICD group (P=0.68). First shock efficacy was 93.8% in the S-ICD group and 91.6% in the TV-ICD group (P=0.40). The first antitachycardia pacing attempt successfully terminated 46% of all monomorphic ventricular tachycardias, but accelerated the arrhythmia in 9.4%. Ten patients with S-ICD experienced 13 electrical storms, versus 18 patients with TV-ICD with 19 electrical storms. Patients with appropriate therapy had an almost 2-fold increased relative risk of electrical storms in the TV-ICD group compared with the S-ICD group (P=0.05).

CONCLUSIONS: In this trial, no difference was observed in shock efficacy of S-ICD compared with TV-ICD. Although patients in the S-ICD group were more likely to receive an ICD shock, the total number of appropriate shocks was not different between the 2 groups. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01296022.

Original languageEnglish
Issue number5
Pages (from-to)321-329
Number of pages9
Publication statusPublished - Feb 2022


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